California officials say a potential rupture from an overheated chemical tank could reduce the risk

A damaged chemical tank in Southern California may have ruptured — potentially reducing the risk of a catastrophic explosion — although an evacuation order remains in effect for about 50,000 residents without a timeline for when they could return, a fire official said Sunday.

Captain Wayhowe Huang of the Orange County Fire Authority said officials will continue to inspect the tank Sunday after emergency crews discovered a crack overnight. As of Sunday morning, he said it does not appear that any highly volatile chemicals in the tank have leaked.

“There is still the risk of a potential explosion. We are not taking it off the table,” Huang said. “We are still working as if that is dangerous.”

Firefighters have been spraying the outside of the tank with water hoses in an effort to cool the burning chemicals inside and prevent an explosion.

Lee Zeldin, the head of the US Environmental Protection Agency, said on Sunday that the “most likely scenario” for now is a “low-volume release,” where officials would be able to “monitor, neutralize and contain the threat.”

“The Orange County Fire Authority is working to keep the tank temperature down. That’s very important,” he told CNN, adding that keeping the temperature below 85 F (29.4 C) is important.

Craig Covey, chief of the Orange County Fire Authority, said the new development could be good.

A possible rupture in the tank “could relieve the existing pressure,” Covey said in a social media video posted Sunday, noting that it still needs to be confirmed.

“It may change the way we move and our strategies,” he said.

A pressurized tank overheated Thursday and began spewing steam at the company’s plant in Garden Grove, about 50 miles southeast of downtown Los Angeles, according to the Orange County Fire Authority.

No injuries were reported. Air monitoring tests so far have found that air pollution at the outlet is within normal limits, and special equipment has been used to ensure that no gas from the tank is dangerous, state and federal environmental officials said Saturday.

Officials said the tank’s valves were broken or “stuck,” preventing crews from releasing the chemical or reducing pressure in the tank, Covey said.

Firefighters’ first hope is to find a way to cool the chemical inside the tank so it doesn’t leak or explode. If that’s not possible, Purdue University engineering professor Andrew Whelton said it would be better if the tank is leaky so the chemicals are contained more.

An explosion that would spread the chemical over a wide area and send shrapnel flying would be the worst case scenario.

If the temperature inside the tank continues to rise, pressure will continue to build as the methyl methacrylate changes from a liquid to a gas, because officials said the pressure relief valves in the tank are no longer working.

Welton said it is unlikely that firefighters would consider creating a hole in the tank for fear of creating a spark that could ignite the flammable and combustible gas.

Efforts to cool the tank appeared to be working on Friday, but Covey backtracked the next day, saying the readings made by the drones actually showed the temperature outside the tank, not inside.

Cooling the tank is important because the flash point of liquid chemicals is 50 F (10 C), according to the National Institute for Occupational Safety and Health.

Citizens file a lawsuit

Meanwhile, some Garden Grove residents filed a class-action lawsuit Saturday against GKN Aerospace Transparency Systems, the company that operates the area where the tank is located.

Lawyers for residents living in the evacuation zone argued in federal court that no matter what happens next, property values ​​in the surrounding community will inevitably be affected.

“There is no positive outcome here for the people who live nearby,” the lawyers wrote in a statement.

“In the best-case scenario, a slow, controlled leak still forces residents out of their homes for an indefinite period, disrupting families, businesses and daily life. In the worst-case scenario, a catastrophic explosion could send debris and debris over a very wide area, damage thousands of buildings and expose residents to serious health risks.”

Those who spoke to the company did not comment on the case itself but pointed to a previous statement about the incident where they apologized to the residents and businessmen who were forced to leave.

“The situation is ongoing and we are fully focused on cooperating with the emergency services, special hazard teams, logistics and the relevant authorities to ensure the safety of the local community, our employees and all stakeholders,” the statement read.

The damaged tank is owned by GKN Aerospace, which makes parts for commercial and military aircraft. It holds between 22,700 and 26,500 liters of methyl methacrylate, which is used to make plastic parts.

Exposure to methyl methacrylate can cause serious breathing problems and cause unconsciousness. It can also cause nerve problems and irritate the skin, eyes and throat, according to fact sheets about the chemical. But Orange County health officials said the chemical is easy to inhale, and residents can be exposed to it in large areas without harm.